'At glacial speed' used to mean something that went very slowly, but with global warming, the glaciers are retreating at a much greater and increasingly faster rate. What is the term that describes this change in phrase usage?
For phrases, I'm not sure I've heard one specifically.
But for single words, like peruse, quite, cleave, I generally see the term contranym and auto-antonym. Wikipedia has a gigantic list of other terms*, but those are the two that I think will be most readily understood.
* antagonym, Janus word , enantiodrome, self-antonym, antilogy, addad, contronym, autantonym
In its blog, Oxford Dictionaries use the term "Shifted Meanings".
Whilst this term can be used for any change in word meaning, it does include words like "egregious", which has become its own opposite:
"Remarkably good" to "remarkably bad".